This invention relates generally to the field of ocean wave energy devices, and more particularly to an improved form adapted to extract maximum energy from each vertical oscillation.
It is known in the art to extract energy by causing an ocean wave to raise and lower a float or buoy in a vertical plane and thereby produce a working force. Workers skilled in this art readily acknowledge that only a small fraction of the total energy contained in a given ocean wave can be captured by any given float or buoy system, unless the natural oscillation frequency of the buoy is in resonance with the then existing ocean wave frequency (wave period). If the frequency of the buoy system is close to, or can be matched, to the wave period, the energy which can be captured is greatly increased. In reality, this state of resonance is very difficult to achieve because ocean wave periods commonly vary from as little as four seconds to as much as twenty second intervals. Floats and buoys, however, have only one natural frequency which is based upon the mass and geometric shape thereof. Therefore, a buoy has only one frequency which will be in resonance with a wave period and all other ocean wave periods will be outside this natural frequency and result in an inefficient energy conversion system.
Another problem of attempting to match natural buoy frequency with ocean wave period frequency lies in the fact that in order to construct a buoy with a natural frequency in the range of ocean wave periods, the buoy construction becomes both very large in terms of mass and awkward in terms of shape.